Spacecraft designers usually have to worry about solar storms, micrometeorites and extreme temperatures. Last week the MESSENGER team prepared to protect the spacecraft from an entirely different sort of storm - Hurricane Isabel.

The team was at work several days before Isabel even came ashore, clearing loose items from the roof of the Applied Physics Laboratory's Kershner Space Building; checking the lightning-protection system of pointed wires that cover the roof; testing and fueling the building's emergency generators; and checking drains to make sure rain water wouldn't back up into MESSENGER's clean room. Finally, as then-Tropical Storm Isabel approached Maryland on September 18, the team placed a scrim cloth cover over MESSENGER to protect against potential drips from above and unplugged its connections to outside power sources - just to make sure a lightning surge wouldn't reach the spacecraft's electronics.

Fortunately, the APL facility suffered no storm damage and the " rain coat" was not needed. The MESSENGER team was back to work on the spacecraft by 7 a.m. on September 19.

MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a scientific investigation of the planet Mercury, and the first NASA mission designed to orbit the planet closest to the Sun. Dr. Sean C. Solomon, of the Carnegie Institution of Washington, leads the mission as principal investigator. The Johns Hopkins University Applied Physics Laboratory in Laurel, Md., is building and will operate the MESSENGER spacecraft and manages the Discovery- class mission for NASA.